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A reliable and specific method for the determination of citalopram enantiomers was developed and validated. Chromatographic resolution of citalopram enantiomers was made on a Shim-pack (5 microm particle size) cyanopropyl column with beta-cyclodextrin (beta-CD) as an effective chiral mobile phase additive. The composition of the mobile phase was (90 + 10, v/v) aqueous 0.1% triethylammonium acetate buffer, pH 4.0 (adjusted with acetic acid), and acetonitrile, containing 12 mM beta-CD. The flow rate was 0.8 mL/min with ultraviolet detection at 240 nm. The effects of the mobile phase composition, concentration of beta-CD, and pH of the triethylammonium acetate buffer on peak shape and resolution of the enantiomers were investigated. The calibration graphs were linear (r = 0.9999, n = 8) in the range of 1-40 microg/mL for S(+) citalopram and R-(-) citalopram. The limit of detection values were 5.51 x 10(-3) and 4.35 x 10(-3) pg/mL, while the limit of quantification values were found to be 1.84 x 10(-2) and 1.45 x 10(-2) microg/mL for S-(+) citalopram and R-(-) citalopram, respectively. 相似文献
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Orange needles of BaEr2S4 are obtained during an investigation of the Ba/Er/U/S system by solid state reaction of a mixture of 238U, Er, BaS, and S in the ratio 1:1:3:3 (evacuated C‐coated fused silica tube, 1273 K, 8 d, cooling rate 3 K/h) together with black crystals of Sb2S3 and US2. 相似文献
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Meccanica - In recent experimental studies an unusual time-dependent transversal behavior of the annulus fibrosus of the intervertebral disc mainly caused by the coupling between mechanics and... 相似文献
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Wireless Networks - In this paper, we solve two problems aiming at improving the secure communications in a one-way relay system. The system under consideration consists of one source, one... 相似文献
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A simple iterative procedure is illustrated here to overcome two problems frequently encountered in hot-wire anemometry: (1) the calibration of hot wires at low velocity and (2) to account for the wall-proximity correction in the actual measurements. The low-velocity calibration method used an iterative correction procedure based on laminar pipe velocity profiles. It is shown that the use of this approach, together with a simple wall proximity correction procedure, provides a simple and accurate calibration of both single and cross hot wires, and gives reliable measurements. 相似文献
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Seyede Maryam Mesbah Namini Afshin Mohsenifar Rezvan Karami Tavoos Rahmani-Cherati Taha Roodbar Meisam Tabatabaei 《Chemical Papers》2015,69(10):1291-1297
Organophosphorus (OP) compounds are extensively used in agricultural practice for pest management. However, their residues have a long half-life in the ecosystem as well as in the agro-products, posing a serious threat to human and animal health. Aryldialkylphosphatase (EC 3.1.8.1) is widely used in detoxification procedures. In the present study, aryldialkylphosphatase was immobilised on synthesised cross-linked nano-sized gel particles, also known as nanogels, in order to enhance the enzyme’s physicochemical properties. Accordingly, a new nanogel consisting of chitosan and myristic acid (CMA nanogel) was synthesised and characterised by way of Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The aryldialkylphosphatase-CMA nanogel conjugate was then assayed by FTIR, and its physicochemical characteristics were also investigated. The data obtained from SEM and TEM showed the nanogels to be homogenous spherical particles less than 50 nm in diameter. The proper formation of the nanogel and nanobioconjugate was also confirmed by FTIR spectra. In comparison with the free enzyme, the pH and thermal stability of the aryldialkylphosphatase were enhanced by the covalent immobilisation. Moreover, the immobilised enzyme could maintain approximately half of its activity over more than one month. The kinetic parameters of the aryldialkylphosphatase-CMA nanogel conjugate were also shown to undergo remarkable improvements, hence the synthesised CMA-nanogel could act as a promising support for aryldialkylphosphatase immobilisation. It is suggested that the aryldialkylphosphatase-CMA nanogel could be used for detoxifying paraoxon; a nerve agent. Further clinical experiments are underway. 相似文献
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W. Hamri O. O. Shyshkina T. M. Tarasiuk T. A. Volovnenko K. Mesbah S. Rhouati Y. M. Volovenko V. V. Medviediev O. V. Shishkin 《Journal of heterocyclic chemistry》2015,52(5):1373-1376
A one‐pot method for the synthesis of 3‐amino‐7‐nitro‐1,2‐dihydroisoquinoline‐4‐carbonitriles from 2‐chloro‐5‐nitrobenzylamines and malononitrile has been developed. 相似文献
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Ahmed SA Odde S Daga PR Bowling JJ Mesbah MK Youssef DT Khalifa SI Doerksen RJ Hamann MT 《Organic letters》2007,9(23):4773-4776
A new latrunculin, oxalatrunculin B (3), was isolated from Red Sea sponge Negombata corticata. Extensive spectroscopic analysis revealed an unprecedented heterocycle in which the rare thiazolidinone ring found in latrunculins was oxidized with three additional oxygens. An actin polymerization inhibition assay agreed with MM-PBSA free energy calculations that 3 binds more weakly than latrunculin B to actin. Significant antifungal and anticancer activity of 3 was found, suggesting an alternate target in addition to actin for latrunculin bioactivity. 相似文献
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Seifeddine Rekkab Mesbah Lahouel Taibi Ben Hadda Caroline Félix Zahia Kabouche 《Comptes Rendus Chimie》2013,16(7):672-678
Four new calix[8]arene sulfonic acids (2a-b, 3a-b) were synthesized. The anticoagulant activity and POM virtual screening of these flexible calixarenes have been established. 相似文献